20 
BULLETIN 571, U. S. DEPARTMENT OF AGRICULTURE. 
Table XVI. — Spraying experiments against the larvse of the pecan leaf case-bearer at 
Monticello, Fla., in 1913. 
Plat Nu ^ ber 
trees. 
Treatment. 
Date of applica- 
tion. 
Results. 
113 
12 
One application of 
paste lead arsenate 
at 3 pounds to 50 
gallons of water. 
Check; untreated. 
Aug. 14 and 15, 
1913. 
Very satisfactory control. Nearly all 
larvae were killed and only a very 
few remained to construct 'hiberna- 
cula in the autumn. Was exceed- 
ingly difficult to detect any hibern- 
acula. No appreciable amount 
of damage was done by the few 
overwintering larvse to the buds 
during the spring. 
As many as 12 hibernacula were 
found around a single bud: the 
average was about 3 hibernacula to 
the bud. During the spring the 
larvae appeared in numbers and 
seriously damaged the buds and 
foliage. Some trees were nearly 
defoliated. 
The results obtained on Plat I, as shown in Table XVI, were highly 
satisfactory, since most of the larvse were killed by the arsenical appli- 
cation. By destroying the larvae during the late summer or early 
autumn, the trees were protected from attacks during the subse- 
quent spring, at which time very serious injuries occur to the buds 
and tender foliage through the peculiar manner of the feeding of 
overwintering larvae. During the following spring (1914), the trees on 
Plat I put forth their foliage in perfect condition, but on account of 
the ravages of the case-bearer larvse the unsprayed trees (Plat II) 
were kept in a state of partial or total defoliation for several weeks, 
and this condition interfered seriously with the setting of nuts. A 
slight arsenical injury was done to the foliage, but in no case was the 
damage so severe as to cause the leaves to drop. 
More extensive spraying experiments were carried out with lead 
arsenate in 1914 than in 1913. Table XVII shows the series of 
experiments conducted in the Abe Simon orchard. 
Table XVII. — Sjiraying experiments against the larvae of the pecan leaf case-bearer at 
Monticello, Fla., in 1914- 
Plat 
No. 
Number 
of 
trees. 
Treatment. 
Date of appli- 
cation. 
Result. 
II 
III 
22 
Powdered lead arsenate at 
2 pounds to 50 gallons of 
water. 
1914 
Aug. 13. 
Check; unsprayed. 
18 
Paste lead arsenate at 3 
pounds to 50 gallons of 
water. 
Aug. 14. 
Practically perfect control. Scarcely 
any larvae succeeded in escaping 
the poison to construct hibernacula. 
Foliage rather seriously injured by 
the heavy application of arsenical. 
Trees were badly infested, as was 
determined by the great abundance 
of hibernacula and the prevalence 
of larvae in the buds during the 
following spring. 
Practically perfect control. Scarcely 
any larvae succeeded in escaping the 
poison to construct hibernacula. 
Foliage rather seriously injured by 
the heavy application of arsenical. 
